Frostbite pre-symptoms are generally cyanosis of the nails, purple, skin erythema, skin lumps, etc., the appearance of the above symptoms, you should consult a doctor in a timely manner. 1. Cyanosis and purple nails: Frostbite is usually preceded by prolonged cold stimulation, insufficient local blood supply, poor venous function, ischemia, hypoxia and cyanosis of the skin and nails, purple symptoms. 2. Skin erythema: frostbite in the early stages of the general will gradually form skin erythema, encounter hot water, warm air, air conditioning and other warm stimuli after the blood supply to improve, and can also cause burning, itching and other symptoms. 3. Skin lumps: pre-frostbite skin lumps of varying sizes may also appear, the pressure of the discoloration, self-consciousness, itching, swelling and pins and needles, may be accompanied by redness and swelling of the skin, bruising, ecchymosis and other manifestations. The appearance of the above symptoms should be taken seriously, but can not rely on a single symptom to determine the condition, it is recommended to consult a doctor in time to confirm the diagnosis and treatment.